Biosensor for bisphenol A leaching from baby bottles using a glassy carbon electrode modified with DNA and single walled carbon nanotubes

We have developed a biosensor for highly sensitive and selective determination of the endocrinic disruptor bisphenol A (BPA). It is based on glassy carbon electrode modified with calf thymus DNA and a composited prepared from single walled carbon nanotubes (SWNT) and Nafion. The interaction between BPA and DNA was studied by voltammetry. The binding constant was determined to be 3.55?×?10³ M^?1, and the binding site has a length of 4.3 base pairs. These electrochemical studies provide further information for a better understanding of the toxicity and carcinogenicity of BPA. Under optimal conditions, the biosensor displays a linear electrochemical response to BPA in the 10 nM to 20 μM concentration range, with a detection limit as low as 5.0 nM (at an S/N of 3). The method was successfully applied to the quantification of BPA in leachates from plastic baby bottles. Recoveries range from 94.0 % to 106.0 % which underpins the excellent performance of this SWNT-based DNA sensor.

Functional graphene-gold nano-composite fabricated electrochemical biosensor for direct and rapid detection of bisphenol A

In this research, the graphene with excellent dispersity is prepared successfully by introducing gold nanoparticle to separate the individual sheets. Various techniques are adopted to characterize the prepared graphene and graphene-gold nanoparticle composite materials. This fabricated new composite material is used as the support material to construct a novel tyrosinase based biosensor for detection of bisphenol A (BPA). The electrochemical performances of the proposed new enzyme biosensor were investigated by differential pulse voltammetry (DPV) method. The proposed biosensor exhibited excellent performance for BPA determination with a wide linear range (2.5 × 10⁻³–3.0 μM), a highly reproducible response (RSD of 2.7%), low interferences and long-term stability. And more importantly, the calculated detection limit of the proposed biosensor was as low as 1 nM. Compared with other detection methods, this graphene-gold nanoparticle composite based tyrosinase biosensor is proved to be a promising and reliable tool for rapid detection of BPA for on-site analysis of emergency BPA related pollution affairs.     

An Electrochemical Aptamer Biosensor for Bisphenol A on a Carbon Nanofibre-silver Nanoparticle Immobilisation Platform

A nanocomposite platform of silver nanoparticles and carbon nanofibres (AgCNFs) was used to immobilise a bisphenol A specific 63-mer ssDNA aptamer to form a biosensor. The fabrication process of the biosensor was studied with electrochemical impedance spectroscopy and cyclic voltammetry in the presence of [Fe(CN)₆]^3−/4− as redox probe. The biosensor detected bisphenol A in a linear range of 0.1–10 nM, with a limit of detection of 0.39 nM using square wave voltammetry (SWV). The biosensor exhibited good selectivity in the presence of interfering species at 100-fold concentrations and was used to detect BPA in real water sample.     

Core-shell Hierarchical Enzymatic Biosensor Based on Hyaluronic Acid Capped Copper Ferrite Nanoparticles for Determination of Endocrine-disrupting Bisphenol A

A novel enzymatic electrochemical biosensor (mCuF/PANI-nf/HA/Lacc/GCE) was designed for detection of bisphenol A (BPA). The copper ferrite nanoparticles was obtained by co-precipitation and its surface was modified with -NH₂ functional organosilane. Polyaniline nanofibers were also synthesized by cyclic voltammetry and characterized by FTIR, XRD, TGA, SEM and TEM, respectively. Then, it was crosslinked with hyaluronic acid as an immobilization matrix for Laccase to adhere to surface of the modified copper ferrites. Cyclic and differential pulse voltammetries were used to evaluate the electrochemical performances of the biosensor, which has a LOD value of 5.40 nM and a LOQ value of 16.20 nM in the 0.01–7.50 μM linear working range. The biosensor was successfully applied for determination of BPA in seawater, canned water and milk samples with recoveries ranging from 96.0 % and 100.7 %. In addition, accuracy of the voltammetric determination method in the real samples was carried out by HPLC and spike/recovery test. The layer-by-layer surface modification strategy of the designed mCuF/PANI-nf/HA/Lacc/GCE biosensor opens a new perspective on both BPA determination and using biopolymer in the structure of enzymatic electrochemical biosensors.     

Gold nanoparticles-enhanced bisphenol A electrochemical biosensor based on tyrosinase immobilized onto self-assembled monolayers-modified gold electrode

A novel electrochemical sensor based on the immobilization of tyrosinase(tyr) onto gold nanoparticles(nano-Au) and thioctic acid amide(T-NH2) self-assembled monolayers(SAMs)-modified gold electrode has been developed for the determination of bisphenol A(BPA).It was found that the nano-Au could significantly enhance the electrochemical response of tyr/nano-Au/T-NH2/Au electrode to BPA,and the enhancement effect of nano-Au on the current response was also related to the enzyme.The results indicated that the biosensor could be used as a detector for BPA determination with a linear range from3.99 ×10-7mol/L to 2.34 ×10-4mol/L and a detection limit of 1.33×10-7mol/L.In addition,this biosensor showed good reproducibility.     

Direct electrochemical detection of bisphenol A at PEDOT-modified glassy carbon electrodes

The electrochemical behavior of bisphenol A (BPA) was studied on poly(3,4-ethylenedioxythiophene) (PEDOT)-modified glassy carbon electrodes by cyclic voltammetry. It was observed that BPA oxidation on PEDOT film produced a BPA polymer (pBPA) showing excellent redox activity with anodic and cathodic peaks at 0.15 and 0.01 V, respectively; the former being evaluated for BPA electrochemical sensing. The amount of deposited pBPA has been estimated by electrochemical and spectroscopic analysis by X-ray photoelectron spectroscopy. The effect of scan rate and pH on the oxidation of pBPA film has been studied. The oxidation current was found to vary linearly with BPA concentration in the range 90–410 μM, and a detection limit of 55 μM was evaluated. Results of BPA amperometric detection have also been collected by using a repetitive potential step program to give a linear response to BPA in the concentration range 40–410 μM with a detection limit of 22 μM and a sensitivity of 1.57 μAμM^?1?cm^?2. The developed sensor showed satisfactory reproducibility and anti-interference properties and was successfully applied to BPA determination in mineral water samples.     

Mesoporous silica-based electrochemical sensor for sensitive determination of environmental hormone bisphenol A

Bisphenol A (BPA) is an emerging contaminant with severe toxic effects such as disrupting endocrine system or causing cancer, therefore, developing sensitive and selective sensor for BPA is very important and interesting. Herein, MCM-41, a kind of mesoporous silica, was synthesized and then used to prepare an electrochemical sensor for BPA. For better comparison, carbon nanotubes, activated carbon, silica gel and graphite were also employed to prepare electrochemical sensor for BPA. The electrochemical behaviors of BPA at different electrochemical sensors were investigated. Compared with other sensors, the MCM-41 sensor greatly enhances the response signal of BPA due to the large active surface area and high accumulation efficiency. The effects of pH value, accumulation time and sensor composition were examined. The linear range is from 2.2 × 10⁻⁷ to 8.8 × 10⁻⁶ mol L⁻¹, and the limit of detection is evaluated to be 3.8 × 10⁻⁸ mol L⁻¹. Finally, the MCM-41 sensor was successfully employed to determine BPA in water samples.     

Sensitive Voltammetric Determination of Bisphenol A Based on a Glassy Carbon Electrode Modified with Copper Oxide‐Zinc Oxide Decorated on Graphene Oxide

A highly sensitive and selective chemical sensor was prepared based on metallic copper‐copper oxides and zinc oxide decorated graphene oxide modified glassy carbon electrode (Cu?Zn/GO/GCE) through an easily electrochemical method for the quantification of bisphenol A (BPA). The composite electrode was characterized via scanning electron microscopy (SEM), X‐Ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy (EIS). The electrochemical behavior of BPA in Britton‐Robinson (BR) buffer solution (pH 7.1) was examined using cyclic voltammetry (CV). Under optimized conditions, the square wave voltammetry (SWV) response of Cu?Zn/GO/GCE towards BPA indicates two linear relationships within concentrations (3.0 nmol L^?1?0.1 μmol L^?1 and 0.35 μmol L^?1?20.0 μmol L^?) and has a low detection limit (0.88 nmol L^?1). The proposed electrochemical sensor based on Cu?Zn/GO/GCE is both time and cost effective, has good reproducibility, high selectivity as well as stability for BPA determination. The developed composite electrode was used to detect BPA in various samples including baby feeding bottle, pacifier, water bottle and food storage container and satisfactory results were obtained with high recoveries.     

Development of an Electrochemical Sensor Based on Covalent Molecular Imprinting for Selective Determination of Bisphenol‐A

In this study, an electrochemical sensor was developed and used for selective determination of bisfenol‐A (BPA) by integrating sol‐gel technique and multi‐walled carbon nanotubes (MWCNTs) modified paste electrode. BPA bounded by covalently to isocyanatopropyl‐triethoxy silane (ICPTS) was synthesized as a new precursor (BPA‐ICPTS) and then BPA‐imprinted polymer (BPA‐IP) sol‐gel was prepared by using tetramethoxysilane (TMOS) and BPA‐ICPTS. Non‐imprinted polymer (NIP) sol‐gel was obtained by using TMOS and (3‐Aminopropyl) triethoxysilane. Both BPA‐IP and NIP sol‐gels were characterized by nitrogen adsorption‐desorption analysis, FTIR, SEM, particle size analyzer and optical microscope. Carbon paste sensor electrode was fabricated by mixing the newly synthesized BPA‐IP with MWCNTs, graphite powder and paraffin oil. The electrochemical characterization of the sensor electrode was achieved with cyclic and differential pulse voltammetric techniques. The response of the developed sensor under the most proper conditions was linear in BPA concentration range from 4.0×10⁻⁹ to 1.0×10⁻⁷ mol L⁻¹ and 5.0×10⁻⁷ to 5.0×10⁻⁵ mol L⁻¹ and the detection limit was 4.4×10⁻⁹ mol L⁻¹. The results unclosed that the proposed sensor displayed high sensitivity and selectivity, superior electrochemical performance and rapid response to BPA.     

A sandwich-type DNA biosensor based on electrochemical co-reduction synthesis of graphene-three dimensional nanostructure gold nanocomposite films

A novel electrochemical DNA biosensor based on graphene-three dimensional nanostructure gold nanocomposite modified glassy carbon electrode (G-3D Au/GCE) was fabricated for detection of survivin gene which was correlated with osteosarcoma. The G-3D Au film was prepared with one-step electrochemical coreduction with graphite oxide and HAuCl₄ at cathodic potentials. The active surface area of G-3D Au/GCE was 2.629 cm², which was about 3.8 times compared to that of a Au-coated GCE under the same experimental conditions, and 8.8 times compared to a planar gold electrode with a similar geometric area. The resultant nanocomposites with high conductivity, electrocatalysis and biocompatibility were characterized by scanning electron microscopy (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). A “sandwich-type” detection strategy was employed in this electrochemical DNA biosensor and the response of this DNA biosensor was measured by CV and amperometric current–time curve detection. Under optimum conditions, there was a good linear relationship between the current signal and the logarithmic function of complementary DNA concentration in a range of 50–5000 fM with a detection limit of 3.4 fM. This new biosensor exhibited a fast amperometric response, high sensitivity and selectivity and has been used in a polymerase chain reaction assay of real-life sample with a satisfactory result.     

Amperometric biosensor for bisphenol A based on a glassy carbon electrode modified with a nanocomposite made from polylysine, single walled carbon nanotubes and tyrosinase

We have prepared a nanocomposite consisting of single-walled carbon nanotubes and polylysine. It was characterized by transmission electron microscopy, X-ray photoelectron spectroscopy, and by UV/vis and FTIR spectroscopy. Tyrosinase was covalently immobilized on the nanocomposite, and the resulting bioconjugate deposited on a glassy carbon electrode to form a biosensor for bisphenol A. The biosensor was characterized by scanning electron microscopy and electrochemical impedance spectroscopy. Under optimized experimental conditions, the biosensor gives a linear response to bisphenol A in the 4.00 nM to 11.5 μM concentration range. Its sensitivity is 788 mA M^?1 cm^?2, and the lower detection limit is 0.97 nM (at an S/N of 3). The biosensor shows good repeatability, reproducibility and long-term stability. In a preliminary practical application, it was successfully applied to the determination of bisphenol A in leachates of plastic spoons.

Electrochemical Sensor Based on Thioether Oligomer Poly(N‐vinylpyrrolidone)‐modified Gold Electrode for Bisphenol A Detection

Presently, bisphenol A (BPA) has been added to the list of substances of very high concern as endocrine disruptors. According to the literature, exposure to bisphenol A even at low doses may result in adverse health effects. In this study, electrochemical sensor of Bisphenol A based on thioether DDT‐Poly(N‐vinylpyrrolidone) oligomer has been developed. The thioether oligomer, which is capable of recognizing BPA, was prepared and used for gold electrode modification. The characterization of the modified gold electrode and the synthesized thioether oligomer were carried out by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), atomic force microscopy (AFM), Fourier‐transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance spectroscopy (¹H NMR) and Size exclusion chromatography (SEC). Obtained results indicate that the modified electrode shows good electrochemical activity, good sensitivity and reproducibility for BPA detection. It exhibited a good linear relationship ranging from 1 to 20 pg/mL, and the detection limit was found to be 1.9 pg/mL at S/N=3. Several interfering species such as hydroquinone, phenol and resorcinol were used and their behaviors on the modified gold electrode were investigated.     

Electrochemical aptasensor for the determination of bisphenol A in drinking water

We present an electrochemical aptasensor for rapid and ultrasensitive determination of the additive bisphenol A (BPA) and for screening drinking water for the presence of BPA. A specific aptamer against BPA and its complementary DNA probe were immobilized on the surface of a gold electrode via self-assembly and hybridization, respectively. The detection of BPA is mainly based on the competitive recognition of BPA by the immobilized aptamer on the surface of the electrode. The electrochemical aptasensor enables BPA to be detected in drinking water with a limit of detection as low as 0.284 pg?mL^?1 in less than 30 min. This extraordinary sensitivity makes the method a most powerful tool for on-site monitoring of water quality and food safety.

Designing and fabrication of a novel gold nanocomposite structure: application in electrochemical sensing of bisphenol A

In this article, a highly sensitive electrochemical sensor is introduced for direct electro-oxidation of bisphenol A (BPA). The novel nanocomposite was prepared based on multi-walled carbon nanotube/thiol functionalised magnetic nanoparticles (Fe₃O₄-SH) as an immobilisation platform and gold nanoparticles (AuNPs) as an amplifying electrochemical signal. The chemisorbed AuNPs exhibited excellent electrochemical activity for the detection of BPA. Some analysing techniques such as Fourier transform infrared spectroscopy, field emission scanning electron microscopy, transmission electron microscopy and energy-dispersive x-ray diffraction exposed the formation of nanocomposite. Under optimum conditions (pH 9), the sensor showed a linear range between 0.002–240 μM, with high sensitivity (0.25 μA μM^?1) along with low detection limit (6.73 × 10^?10 M). Moreover, nanocomposites could efficiently decrease the effect of interfering agents and remarkably enhance the utility of sensor at detection of BPA in some real samples.     

Electrochemical bisphenol A sensor based on N-doped graphene sheets

Bisphenol A (BPA), which could disrupt endocrine system and cause cancer, has been considered as an endocrine disruptor. Therefore, it is very important and necessary to develop a sensitive and selective method for detection of BPA. Herein, nitrogen-doped graphene sheets (N-GS) and chitosan (CS) were used to prepare electrochemical BPA sensor. Compared with graphene, N-GS has favorable electron transfer ability and electrocatalytic property, which could enhance the response signal towards BPA. CS also exhibits excellent film forming ability and improves the electrochemical behavior of N-GS modified electrode. The sensor exhibits a sensitive response to BPA in the range of 1.0 × 10⁻⁸–1.3 × 10⁻⁶ mol L⁻¹ with a low detection limit of 5.0 × 10⁻⁹ mol L⁻¹ under the optimal conditions. Finally, this proposed sensor was successfully employed to determine BPA in water samples with satisfactory results.     

Sensitive determination of bisphenol A in plastic products by derivative voltammetry using an acetylene black paste electrode coated with salicylaldehyde-modified chitosan

A sensitive and reliable electrochemical method was developed for determination of bisphenol A (BPA) in plastic products using an acetylene black paste electrode coated with salicylaldehyde-modified chitosan (denoted as S-CHIT/ABPE). In the second-order derivative linear sweep voltammetry technique, BPA yielded a very sensitive and well-defined oxidation peak at 842?mV in 0.2?mol?L^?1 HCl solution. Owing to its unique structure and extraordinary properties, S-CHIT/ABPE showed higher accumulation efficiency toward BPA compared with bare ABPE, and significantly enhanced the oxidation peak current of BPA. Under the optimum conditions, the oxidation peak current was proportional to the concentration of BPA over the range of 4.0?×?10^?8?mol?L^?1?～?1.0?× 10^?5?mol?L^?1. The detection limit (S/N?=?3) was 2.0?×?10^?8?mol?L^?1. The fabricated S-CHIT/ABPE not only exhibited strong adsorption capacity toward BPA, but also provided remarkable stable and quantitatively reproducible analytical performance. Additionally, this newly-developed method possesses some obvious advantages including high sensitivity, extreme simplicity, rapid response and low cost.     

Glucose Biosensor Based on the Fabrication of Glucose Oxidase in the Bio-Inspired Polydopamine-Gold Nanoparticle Composite Film

A highly efficient enzyme immobilization method has been developed for electrochemical biosensors using polydopamine films with gold nanoparticles (AuNPs) embedded. This simple enzyme fabrication method can be performed in very mild conditions and stored in a long time with high bioactivity. The fabricated amperometric glucose biosensor exhibited a high and reproducible sensitivity, wide linear dynamic range and low limit of detection (LOD) (0.1 μmol·L^?1). A low value of 1.5 mmol·L^?1 for the apparent Michaelis‐Menten constant K^app_M was obtained. The high sensitivity, wide linear range, good reproducibility and stability make this biosensor a promising candidate for portable amperometric glucose biosensor.     

A Sensitive Biosensor for Determination of Cu2+ by One‐step Electrodeposition

A simple one‐step electrodeposition method is described to fabricate three dimensional ordered macroporous chitosan?prussian blue?single walled carbon nanotubes (3DOM CS?PB?SWCNTs) film onto the gold electrode surface to fabricate a copper ions (Cu²⁺)‐specific DNAzyme biosensor. The new sensing strategy for sensitive and selective detection of Cu²⁺ was based on Au nanorods (AuNRs) as signal amplification labels. The electrochemical signal of glucose increased with the concentration of Cu²⁺ increasing. The morphologies and electrochemistry of the composites were investigated by using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electrochemical techniques including cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) and so on. Linear correlations of copper ion concentration were obtained in the range from 10^?18 M to 10^?5 M, achieving with a limit of detection of 10^?19 M (S/N=3). Parameters affecting the biosensor response such as temperature, the cleavage time and the time of hybridization were optimized. This biosensor showed a wide range, low detection limit, good reproducibility and high stability. Additionally, these striking properties endow the biosensor with a great promise for analytical applications.     

A Glucose Biosensor Based on Immobilization of Glucose Oxidase on Platinum Nanoparticle Doped Santa Barbara Amorphous Material-15

A novel electrochemical glucose biosensor was prepared by combining platinum nanoparticle doped Santa Barbara Amorphous Material 15 with glucose oxidase. The resulting material demonstrated high stability and reactivity for catalyzing glucose electrolytic oxidation, primarily due to the high surface area of these catalysts. This glucose biosensor was capable of interference-free determination of glucose with a linear dynamic range from 0.03 to 12.0 mmol L^?1. In addition, it has the advantages of simple preparation and good stability. The reported method is promising for the determination of glucose in human serum.